Methods for eluting river and lake sediments with controlled release of aggregated pollutants

Abstract

This invention relates to a method for eluting river and lake sediments with controlled release of aggregated pollutants, comprising: determining the fragmentation sensitivity under disturbance by measuring the binding energy of micro-aggregates in the sediment, including electrostatic force and organic cementation strength; establishing the aggregate stress-response relationship to predict the structural disintegration behavior under disturbance shear rate; classifying aggregates into easily breakable, controllably breakable, and stable types; fitting the disturbance parameters of shear rate and fluid kinetic energy with the pollutant release rate to determine the nonlinear threshold range; setting a disturbance threshold window so that the disturbance energy is between the aggregate decomposition initiation point and the pollutant overflow point; and controlling the disturbance rhythm to guide the orderly disintegration of aggregates. This invention, by establishing a response model between the disturbance shear rate and aggregate disintegration behavior, identifies key structural breakage points and pollutant release inflection points, and constructs a disturbance-release nonlinear function relationship, effectively avoiding the instantaneous release of pollutants caused by excessive disturbance in traditional elution methods.

Description

TECHNICAL FIELD

[0001] The present application relates to a river and lake sediment elution method, in particular to a controllable agglomerate pollutant release river and lake sediment elution method. BACKGROUND

[0002] In combination with the prior art document CN2011103548334, a contaminated water body sediment elution in-situ position replacement pollution cleaning equipment, the present application proposes a combined technical path of physical disturbance release, magnetic loading flocculation, water pumping and backflow, which to some extent realizes the in-situ pollution cleaning treatment of the contaminated sediment. The core technical idea is to release the pollutants into the water by disturbance, and then separate the pollutants from the water body with the help of magnetic flocculants, to realize the pollution removal process of elution-separation-backflow-filtering. Although this scheme has certain process integrity and engineering implementability in practical application, there are still many technical deficiencies and potential drawbacks that cannot be ignored under the key pollution process management goal of controllable agglomerate pollutant release.

[0003] Firstly, the disturbance process in the prior art adopts a single mechanical disturbance method, which lacks accurate identification of the mechanical properties and disintegration threshold of the sediment aggregate structure. The disturbance intensity and duration are not scientifically set based on the cementation strength and structural response characteristics of the pollution aggregate, but directly disturb the sediment on a large scale. This extensive disturbance method is easy to cause the overall disintegration of the aggregate, thereby releasing a large amount of endogenous pollutants (such as ammonia nitrogen, total phosphorus, COD, etc.) in a very short time, causing a sharp rise in the instantaneous concentration of pollutants, forming a peak of water pollution, and even causing secondary pollution risk. In addition, the design lacks nonlinear response analysis between the shear rate and the release rate of pollutants, and does not introduce a key structural breaking point identification mechanism, which cannot effectively determine when the disturbance reaches the critical point of the sudden release of pollutants, thereby losing the ability to predict and control the pollution release process. Secondly, in the interface control of the pollution release path, the invention only relies on the subsequent magnetic loading separation process for pollution removal, ignoring the value of the water-sediment interface as the initial release window of pollutants. In essence, this design separates the release of pollutants from the control of pollutants into two stages, lacking real-time interception, interface settlement guidance, and process regulation means for pollutant retention and slow release. For example, this method does not consider constructing a water-sediment interface adsorption barrier or inducing a settlement layer after disturbance, which makes it difficult for some pollutants with small particle size or in dissolved state to be captured by magnetic flocs in time, and easily expands to the upper water body with water disturbance, forming persistent pollution. The present invention emphasizes establishing a functional relationship between disturbance input and pollution output through a nonlinear disturbance function during the disturbance process, and immediately constructing a secondary buffer layer after the disturbance stops to ensure that pollutants achieve in-situ settlement, stable coating, and dynamic passivation at the interface, forming a closed-loop system for the whole process of disturbance-release-settlement-control. Thirdly, in the feedback mechanism of pollution control, the prior art does not integrate any dynamic adjustment mechanism based on real-time response of pollutant concentration, and the device operating parameters are basically preset fixed values, which cannot cope with the mutation of pollution release rate or the uncertainty of structural changes during the disturbance process. In actual engineering, the structure, cementation strength, and pollutant load of pollution aggregates differ significantly between different regions, and the pollution release behavior during the disturbance process has strong nonlinearity and uncertainty. Without real-time feedback system, the pre-set disturbance parameters cannot accurately control the pollution release process, which is prone to the problems of excessive disturbance or insufficient disturbance. SUMMARY

[0004] The purpose of the present invention is to provide a controllable aggregate pollution release method for river and lake sediment elution, thereby solving some of the problems and deficiencies pointed out in the background art.

[0005] The present invention solves the above technical problems by adopting the following technical solution, which includes the following steps:

[0006] The breaking sensitivity under disturbance is judged by measuring the micro-agglomerate binding energy including electrostatic force and organic cementation strength in the sediment; the stress response relationship of the agglomerate is established to predict the structural disintegration behavior under the disturbance shear rate; the agglomerate is divided into easy-breaking type, controllable breaking type and stable type;

[0007] The disturbance parameters of shear rate and fluid kinetic energy are fitted with the release rate of pollutants to determine the non-linear threshold interval; the disturbance threshold window is set so that the disturbance energy is between the decomposition starting point of the agglomerate and the overflow point of the pollutants; the disturbance rhythm is controlled to guide the orderly disintegration of the agglomerate;

[0008] The interface conditions of pH and potential difference are used to adjust the diffusion of pollutants in the interface layer; the released pollutants are guided to form charge exchange and complex reactions with the in-situ control agent of natural clay layer and charge adjusting particles; the release path of the three of pollutants, interface and water body is controlled to form a retention layer of pollutants in the interface; the steady state relationship between disturbance input and pollution release output is dynamically coordinated, and the residual pollutants after release are settled to the surface layer of the sediment through the interface retention layer to build a secondary buffer layer.

[0009] Further, the method for predicting the structural disintegration behavior under the disturbance shear rate comprises:

[0010] The structural characteristics of the pollution agglomerate in the sediment are analyzed in-situ to obtain the particle size distribution, component composition, bonding type and cementation strength information of the agglomerate; the mapping relationship between the disturbance shear rate and the response of the agglomerate structure is established to predict the structural integrity change trend of the pollution agglomerate under a given disturbance shear rate, and to identify the key structural breaking point.

[0011] Further, the structural characteristics of the agglomerate include the physical combination and chemical bonding state among inorganic particles, organic matter and microbial extracellular polymers; the mapping relationship between the disturbance shear rate and the response of the agglomerate structure is established based on the gradual change process of structural deformation, micro-crack formation and cementation failure of the agglomerate under disturbance; the key structural breaking point refers to the critical disturbance shear rate at which the main combination structure inside the agglomerate reaches the failure state.

[0012] Further, the method for determining the non-linear threshold interval comprises:

[0013] The pollution release rate data of the pollution agglomerate under different disturbance shear rates or fluid kinetic energy conditions are obtained, and the continuity curve between the disturbance shear parameters and the response of the pollution release is established;

[0014] The release acceleration change inflection point in the response curve is identified as the critical strength of rapid release of pollutants;

[0015] The release stable interval and the disturbance range before the release mutation are jointly defined as a nonlinear threshold interval of the disturbance control, and the threshold interval is used to adjust the disturbance intensity of the sediment elution operation.

[0016] Further, the pollutants include one or more of total phosphorus, ammonia nitrogen, chemical oxygen demand (COD), and heavy metal ions; and the continuity response curve is a nonlinear relationship curve between the disturbance shear rate and the pollutant release amount per unit time, and is used to identify the mutation critical point of the pollutant release in the disturbance process.

[0017] Further, the nonlinear threshold interval is established by collecting multiple groups of pollutant release data under different disturbance intensities, and is dynamically corrected according to real-time data in the actual elution process; and the nonlinear threshold interval is used to control the operating parameters of the disturbance equipment, so that the disturbance intensity is within the stable release range of the pollutants.

[0018] By constructing a nonlinear dynamic function model between the disturbance shear intensity and the pollutant release rate, a stable release interval of the pollutants is identified in the disturbance parameter space, that is, a nonlinear threshold interval of the disturbance intensity, and the operating parameters of the disturbance equipment are controlled through the interval. A response curve of the disturbance intensity and the pollutant release is established by using multiple groups of disturbance test data, and then a dynamic response correction mechanism is introduced, so that the system can dynamically fine-tune the threshold interval according to the real-time pollutant release data collected in the actual elution process, to realize stable mapping of the disturbance input and the pollutant output.

[0019] The disturbance and release response function in a non-public structure form is adopted:

[0020]

[0021] Wherein:

[0022] represents a disturbance influence function, and represents a disturbance intensity cumulative response of the pollutant release behavior; represents a change rate of the disturbance shear rate in time ; represents an instantaneous release rate of the pollutant in the disturbance time ; represents an adjustment coefficient, which respectively controls the influence intensity of the shear driving term and the release reaction term; represents a disturbance sensitivity coefficient, which is used to adjust the nonlinear degree of the shear rate change on the system response; represents a pollutant release inhibition decay coefficient, which controls the response hysteresis of the release behavior to the disturbance; represents a structure disturbance cycle parameter, which simulates the structure rupture cycle characteristics in the agglomerate decomposition process; represents a disturbance intensity; with represent the start and current time of the perturbation process respectively.

[0023] Through the calculation and dynamic integration evaluation of the function in the actual elution process, it can be judged whether the disturbance is in the stable interval of pollutant release. If located in the stable platform range of the function, it indicates that the disturbance intensity control is appropriate; once deviating from the stable interval, the system starts the feedback mechanism to automatically adjust the input parameters (such as shear frequency, fluid kinetic energy, and disturbance rhythm) of the disturbance device, and pulls the disturbance intensity back to the stable pollutant release threshold.

[0024] Further, the method for constructing the secondary buffer layer comprises: forming a flow velocity slowing zone at the water-sediment interface to promote the settlement of pollutants by regulating the hydrodynamic conditions in the disturbance stop stage; placing a guided settlement material at the water-sediment interface region for adsorbing or complexing the released pollutants; and adjusting the microenvironment parameters of the interface layer, including pH, potential or redox conditions, to make the settled pollutants form a retention deposition structure on the surface layer of the sediment.

[0025] Further, the guided settlement material is a material with charge adsorption capacity or high specific surface area, selected from modified clay, biochar, zeolite, or composite particle materials thereof; and the microenvironment parameters of the interface layer are controlled by adding acid-base regulators, slow-release oxidizing agents or microbial regulators to stabilize the deposition state of the pollutants in the surface sediment.

[0026] Further, the secondary buffer is used to capture residual pollutants that have not completely settled or have entered the water body after disturbance; and the construction process of the secondary buffer layer is continuously connected with the disturbance elution process, forming a closed-loop pollution control process of disturbance control, pollutant release, resedimentation and interface stabilization.

[0027] The river and lake sediment elution method of the controllable aggregate pollutant release of the application realizes the precise regulation and risk closed-loop management of the whole process of the sediment endogenous pollutant elution by identifying the structural characteristics of the pollution aggregate, dynamically controlling the disturbance shear response, adjusting the interface of the pollutant release path, and the secondary settlement and stabilization of the residual pollutants after release.

[0028] By establishing a response model between the disturbance shear rate and the aggregate disintegration behavior, identifying the key structure breaking point and the pollutant release inflection point, and constructing a disturbance-release nonlinear function relationship, the instantaneous pollutant burst caused by excessive disturbance in the traditional elution can be effectively avoided, and the precise prediction and dynamic adjustment of the pollutant release can be realized.

[0029] By setting the nonlinear threshold interval of disturbance intensity and controlling the disturbance rhythm, the present application guides the gradual disintegration of the pollution aggregate, improves the elution efficiency, significantly reduces the fluctuation amplitude of the pollutant release, reduces the secondary pollution risk in the disturbance process, and improves the water quality guarantee capability of the elution operation. The secondary buffer layer is constructed by adding composite materials (such as modified biochar, clay, zeolite, etc.) with high specific surface area and charged adsorption capacity, and the microenvironment conditions such as pH, potential, oxidation and reduction are adjusted, so that the pollutants that are not completely settled or migrate again after disturbance are effectively intercepted, a stable interface retention structure is formed, and the re-deposition ability of the released pollutants is enhanced. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 The pollution aggregate microstructure measurement and grading flowchart of the present application.

[0031] Figure 2 The disturbance-release-regulation function relationship diagram of the pollution aggregate of the present application.

[0032] Figure 3 The function relationship diagram of the interface layer adjustment on the pollutant release path of the present application.

[0033] Figure 4 The disturbance response flowchart and structure mechanism diagram of the A lake sediment pollution aggregate of example 1 of the present application.

[0034] Figure 5 The disturbance-release-feedback closed-loop control process flowchart of the A lake sediment of example 2 of the present application.

[0035] Figure 6 The interface secondary buffer layer construction and pollution stable control system diagram of example 3 of the present application. DETAILED DESCRIPTION

[0036] The specific embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0037] The specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. Figure 1As shown, for the pollution micro-aggregates existing in the sediment of water body, the micro-scale structure measurement means is used to collect the bonding structure parameters in situ, specifically including the multi-dimensional binding energy indexes such as the electrostatic force between inorganic particles in the aggregate, the cementing strength between organic matters, the adhesive film layer formed by microbial secretions and the like, and the data is obtained through in-situ micro indentation, potential scanning and chemical bond energy probe and the like, so as to construct a comprehensive binding energy model of each type of aggregate. After obtaining the binding energy parameters, the microstructure characteristics are associated with the external disturbance conditions, and the stress response relationship of the aggregate is established, that is, whether the mechanical impact of the disturbance shear rate on the structure of the aggregate reaches the bonding rupture threshold value, so as to predict whether the structure of the aggregate will be disintegrated under the given disturbance condition. In order to realize quantitative evaluation, the present application further simulates the structure evolution process of the aggregate under different shear rates through disturbance experiment, captures the morphological change, internal crack propagation and surface peeling path before disintegration, and accordingly extracts the sensitive response characteristics of each type of aggregate to disturbance.

[0038] According to the above structure response characteristics and disintegration behavior mode, the pollution aggregate is divided into three types according to its breaking critical energy level and release risk: easy-to-break type, controllable breaking type and stable type, wherein the easy-to-break type aggregate is disintegrated and releases pollutants under low disturbance energy, and needs to be protected and delayed disturbance; the controllable breaking type aggregate can be disintegrated gradually in the medium disturbance interval, and is suitable for being eluted in order through disturbance rhythm regulation mode; the stable type aggregate has high binding energy and anti-disturbance, and basically maintains the structural integrity under the conventional elution condition, and can be considered to enhance the disturbance or assist in removing through the matching breaking mechanism.

[0039] Combined with the drawings Figure 2 As shown, adjustable hydraulic disturbance devices are used to carry out staged disturbance experiments on the identified types of pollution aggregates under different shear rates and fluid kinetic energy intensities, real-time monitor and record the release rate of pollutants under the corresponding disturbance parameters, including but not limited to key indexes such as ammonia nitrogen, total phosphorus, COD and the like, and input the data into the calculation model for fitting processing. The fitting process adopts high-dimensional nonlinear regression or customized composite response function, captures the nonlinear turning point between the disturbance intensity change and the release rate of pollutants, identifies the significant slope change, release acceleration stage and inflection point threshold existing in the release curve, so as to determine the nonlinear threshold interval of the disturbance intensity, that is, the disturbance window range in which the structure of the aggregate begins to loosen but the pollutants have not yet been released on a large scale.

[0040] Subsequently, a disturbance threshold window is set on the basis of the threshold interval, the lower limit of which corresponds to the initial breaking point of the aggregate structure, and the upper limit of which corresponds to the critical shear strength at which the release of pollutants significantly increases, ensuring that all disturbance energy is always controlled within a dynamic balance range in which the structure disintegration is controllable and the pollution release is suppressible. During the disturbance operation, the system implements an intermittent disturbance strategy by finely adjusting the rhythm parameters such as the disturbance frequency, energy density, and time interval, guiding the aggregate structure to gradually peel off from the surface layer, crack into the middle layer, and then release from the core, forming an "ordered disintegration" process on the physical path, and avoiding the triggering of overall instability of the aggregate and the instantaneous burst release of pollutants due to continuous disturbance. At the same time, the disturbance rhythm strategy can be dynamically adjusted in combination with the online monitoring results of pollutants, and when the release rate approaches the upper limit of the threshold window, the disturbance intensity is automatically reduced or the disturbance period is extended, realizing closed-loop self-stable control between the disturbance rhythm and the release rate.

[0041] In combination with the accompanying Figure 3 The present embodiment introduces an interface layer physical and chemical regulation mechanism to strengthen the interface control and resedimentation guidance of the pollution release path. Specifically, during and at the later stage of the disturbance operation, a microenvironment regulation system is constructed by adjusting the pH value and potential difference at the water-mud interface. This system can form an interface barrier with selective adsorption and charge shielding function by releasing a small amount of alkaline buffer in situ or applying an electrochemical microelectric field, and regulate the diffusion behavior of pollutants at the interface. After the release of pollutants from the aggregate, the migration rate in the interface layer is significantly reduced. At the same time, in-situ regulating agents with high charge density or surface complexing capacity are pre-disposed in the interface region, such as natural bentonite, clay particles loaded with metal oxides, or composite charge adjusting materials. The released pollutant molecules undergo directional charge exchange reactions and complex formation behaviors with these materials in the interface layer, thereby realizing in-situ capture, transformation, or passivation of pollutants, and reducing their tendency to enter the overlying water body. This process not only changes the diffusion dynamics of pollutants, but also forms a highly active pollution retention zone at the water-mud interface. This retention zone has good resorption and structural stability, and can gradually guide the released pollutants that have not completely migrated to settle to the surface layer of the sediment after the disturbance is weakened or terminated, thereby forming a functional "secondary buffer layer". Compared with the original sediment, this buffer layer has better adsorption capacity and barrier performance, and can continue to intercept and release residual pollutants when the hydrodynamic disturbance is restored or the external conditions change, preventing them from floating again or migrating into the water body, and realizing closed-loop control of the whole process of the disturbance release path.

[0042] Furthermore, to ensure the dynamic coordination of the process, the application synchronously establishes a real-time monitoring mechanism between the disturbance input intensity and the pollution release output rate. When the release rate approaches the upper limit or the interface adsorption tends to be saturated, the system automatically adjusts the disturbance energy level and the interface condition parameters, so that the entire "disturbance-release-interface migration-resettling" process is maintained within the state interval of pollution balance retention and stable transfer. Through the synergistic regulation mechanism of interface layer materialization adjustment and release path reconstruction, combined with the disturbance response model and the material guided settling strategy, the application constructs an efficient, safe and intelligent pollution release and resettling system, effectively reduces the subsequent pollution release risk in the sediment elution process, and significantly improves the stability and ecological friendliness of water environment governance.

[0043] Example 1

[0044] In combination with the Figure 4 , a typical eutrophic lake: A lake in the southwest nearshore sedimentation area as the experimental object. Due to slow water flow and weak water exchange capacity, the sediment pollution in this area accumulates significantly, and the aggregates are rich in nitrogen, phosphorus, COD and heavy metals, which is the key area for in-situ remediation of sediment. Through field sampling and in-situ laboratory testing, the micro-aggregate structure characteristics of the sediments in the range of 20-40 cm deep layer of the lake bottom are identified, and the laser particle size analyzer and the frozen scanning electron microscope are used to measure the main aggregate particle size distribution concentrated in 20-75 μm, among which the fine flocculent body and algal aggregate are mainly. The organic matter content of the aggregate is 7.3%, and the obvious humic acid cementing layer is contained in the cementing component, and the average cementing strength is , indicating that the structure has a potential instability risk under moderate disturbance.

[0045] After obtaining the above basic structure data, the disturbance elution operation is simulated in the form of rotating shear disc, the shear rate is set to increase from to , the structure response behavior of the aggregate under each level of disturbance is observed, and the change of the pollution release rate is recorded. The results show that when the shear rate is , the aggregate begins to deform loosely, and the flocculent edge peels off; when the shear rate is , a large number of hollow structures are broken and release the embedded pollutants, and the release rate increases significantly; when the shear rate exceeds , the particle disintegration is almost complete, and the pollution release rate reaches the peak, the phosphorus concentration jumps from the original 1.2 mg / L to 3.6 mg / L, the ammonia nitrogen increases from 0.8 mg / L to 2.9 mg / L, and the COD release rate increases to 6.5 mg / L·h. Based on this, the application constructs the mapping function between the disturbance shear rate and the integrity of the aggregate and the release rate The correlation was found to exhibit typical nonlinear characteristics, at shear rate There is a significant abrupt change in response within the interval, therefore... Identified as a critical point (initiation point) for aggregate rupture, As the inflection point (overflow point) of pollutant release, the disturbance threshold window is set accordingly. .

[0046] In subsequent on-site semi-physical experiments, the disturbance intensity was selected to be controlled at... The phosphorus concentration was monitored using a real-time online sensing system and kept within the range of 2.0–2.4 mg / L. The pollutant release curve did not fluctuate drastically. The agglomerate breakup process progressed layer by layer from the outside to the inside. The particle structure did not collapse as a whole, and the pollutant release remained within a controllable rate.

[0047] Typical pollutant aggregates were extracted from sediment samples at the bottom of Lake A. After freeze-drying and separation screening, the dominant aggregate type with a particle size range of 25–60 μm was obtained. Simultaneous scanning electron microscopy (SEM) coupled with Fourier transform infrared spectroscopy (FTIR) revealed that the internal structure of the aggregates exhibited a multi-layered coating. Inorganic mineral particles (mainly quartz and clay minerals) accounted for approximately 40% of the skeleton, while the outer layer was mainly composed of organic matter, including humic acid and fulvic acid, as well as a large amount of extracellular polymeric substances (EPS) formed by microorganisms. The latter formed a highly adhesive cross-linked layer on the surface of the structure. The local structural strength was tested using nanoindentation and in-situ tensile tests, which showed that the inorganic particles were mainly physically tightly packed, with relatively weak binding forces.

[0048] The main bonding mechanism between the organic layer and EPS is through hydrogen bonding, hydrophobic interactions, and partial metal bridging, with an average bonding strength of [value missing]. The maximum local fracture strength point can reach Subsequently, a continuously adjustable shear rate gradient was applied to the aforementioned aggregates in a perturbation simulation apparatus. to Within the range With a step size of 5 minutes, the structure was perturbed in segments for 5 minutes each, and the structural response was recorded in real time. It was found that when the shear rate was 100%, the perturbation was 5 minutes each. At that time, the surface of the aggregates began to deform, and slight cracks appeared in the EPS layer; The first microcracks appeared in the surface bonding zone, releasing some of the adsorbed phosphorus; when the perturbation rate increased to A through crack appeared in the middle of the structure, the EPS layer was broken over 45% of the area, and the bonding strength decreased by more than 30%. When the fracture of the organic cementation zone extends to the core layer, the structure disintegrates in a large area and releases a significant pollutant peak, at which time the phosphorus concentration increases from 1.3 mg / L before disturbance to 2.8 mg / L, and the ammonia nitrogen increases from 0.9 mg / L to 2.4 mg / L. By fitting the structural response index (characterized by the crack density and the integrity of the cementation zone) with the shear rate , a continuous response curve is obtained, and the starting point of the structure instability is identified as , and the key structural fracture point of the complete failure of the cementation main structure is identified as . The experiment further uses to represent the pollutant release rate, and the coupling window between the structure disintegration and the pollutant release is confirmed by superimposing the analysis, which shows that if the disturbance is controlled within , the pollutant release rate can be stabilized within an acceptable range (such as the phosphorus concentration controlled within 2.0-2.3 mg / L) while the agglomerate peels off layer by layer, which meets the goal of structure breakage and pollution control.

[0049] To verify the feasibility of the model in actual engineering application, the adaptive disturbance system is used in the A lake treatment engineering pilot to set the shear rate control range as , and the elution operation is performed on a sediment area with an area of about 120 m², and the online water quality sensing system is used for monitoring the pollutant release throughout the process. The results show that the structural response of the agglomerate during the disturbance process conforms to the prediction model trend, the pollutant release curve is smooth without peak fluctuation, the elution efficiency is improved by 17%, and the water quality stability risk is reduced by about 43%. Thus, it is verified that the multiple binding modes among the inorganic particles, organic matter and extracellular polymers in the agglomerate are identified in the present application, and the disturbance response model is constructed based on the structural deformation, micro-crack evolution and cementation failure.

[0050] Example 2:

[0051] In combination with the Figure 5 , this embodiment relies on the pollution agglomerate elution test in the southwest area of A lake to carry out the system disturbance response experiment and dynamic modeling verification. First, the sediment samples within a depth of about 30 cm from the bottom of the lake are collected, and the agglomerate separation and extraction process is used to obtain the medium organic matter content agglomerate samples with a particle size concentrated between 30-80 μm, and the composition analysis determines that the agglomerate is rich in carbon source organic matter (about 32% of the total mass), clay mineral particles (mainly illite and montmorillonite), and obvious extracellular polymer (EPS) cementation network, and the pollutant content is concentrated in total phosphorus (TP) 2.1 mg / g, ammonia nitrogen (NH4-N) 1.6 mg / g, and COD about 18.5 mg / g.

[0052] In the experimental stage, the disturbance shear rate setting range is constructed as​​​ Every As one level of disturbance, aggregate samples were subjected to treatment in a shear cell for 5 minutes, and the pollutant release rate was measured in real time using a flow-through detection cell. The results are shown below: Shear rate Within this range, the pollutant release rate increases slowly, with TP release rate ranging from 0.15 to 0.28 mg / L·min. The release rate is approximately 0.12–0.22 mg / L·min; from The release curve showed a significant acceleration, with the TP release rate increasing to 0.41 mg / L·min. It reached 0.75 mg / L·min; while at the shear rate Between these times, TP release suddenly increased to 1.2 mg / L·min. When the release rate exceeds 0.9 mg / L·min, the slope of the release curve increases sharply, constituting an inflection point for accelerated release; further increasing the perturbation to Subsequently, the release rate slowed down and stabilized in the range of 1.3–1.4 mg / L·min, showing a release plateau.

[0053] Based on the above experimental data, the perturbation shear rate was plotted. With pollutant release rate The continuous response curves revealed that the release process can be divided into three stages: the first stage is... The first phase is a slow release phase, and the second phase is... The nonlinear accelerated release phase, the third phase is The above high plateau periods, among which The steepest slope of the interval release curve constitutes the critical disturbance intensity for the rapid release of pollutants.

[0054] The present invention is based on this The range is defined as the release stable interval, and Set to quickly release the inflection point window and lock the full disturbance control range to [value]. The nonlinear disturbance threshold range was used as the basis for setting the disturbance intensity for subsequent elution operations. To further verify its engineering application value, an underwater disturbance arm system was deployed in the dredging and elution pilot area of ​​Lake A, and the disturbance shear intensity was controlled within a certain range. , matching the optimal control points identified before, under the same sediment composition and aggregate structure conditions, a continuous elution operation of 300 m² area was carried out, the results showed that the pollutant release rate recorded by the online monitoring system remained between TP 0.52-0.61 mg / L·min, the change was smooth, there was no sudden release peak, the TP concentration in the treated water body increased stably by no more than 1.5 times, the pollutant did not appear sudden increase, the system control ability was good. At the same time, the disturbance efficiency was improved by about 19% compared with the original set fixed flow rate, and the subsequent recovery period of the water body was shortened by more than 30%, which showed that by determining the nonlinear mapping relationship between the disturbance shear parameter and the pollutant release response, combined with the release acceleration inflection point judgment and threshold control interval division, scientific basis could indeed be provided for the setting of the disturbance intensity of the sediment,

[0055] This embodiment continues to take the southwest sedimentation area of A lake as the test scene, collects typical eutrophic aggregate sediment samples, and constructs a shear rate disturbance platform in the laboratory to simulate the pollutant release behavior under different hydrodynamic disturbance conditions, sets the range of disturbance shear rate to , takes as the incremental step, a total of 18 groups of disturbance conditions, each group of disturbance action time is 5 minutes, collects release water samples and analyzes the pollutant release amount per unit time, and then draws the continuity response curve of disturbance shear rate and pollutant release amount per unit time , the experimental data are as follows: when the shear rate is , the TP release amount rises slowly, between 0.12-0.27 mg / L·min, the COD release amount is 2.3-3.8 mg / L·min, is 0.16-0.29 mg / L·min, and concentrations hardly change, indicating that the aggregate structure is in a stable state, only the surface flocculent or weakly bound layer appears slightly broken.

[0056] When the shear rate is increased to , the TP release amount increases significantly to 0.48-0.91 mg / L·min, the release amount reaches 0.63-1.1 mg / L·min, the COD peak breaks through 5.2 mg / L·min, and the release concentration exceeds 0.02 mg / L for the first time, the release also rises to 0.015 mg / L, the release amount appears an inflection point when the shear rate is , the slope of the TP and COD release curves increases from the previous average of 0.03 to 0.09, forming an obvious accelerated release trend; continue to increase the disturbance to ​Afterwards, the pollutant release rate entered a plateau stage as a whole, the TP release rate maintained at 1.1-1.3 mg / L·min, maintained at 1.2-1.4 mg / L·min, the COD maintained at 5.5-6.3 mg / L·min, the heavy metal concentration fluctuated slowly, and the response curve presented a typical S-shaped nonlinear trend, thus confirming that the shear rate was a mutation critical point of pollutant release.

[0057] Further overlapping comparison of the release rates of TP and COD found that the changes of both in the shear interval were highly coordinated, with a Pearson correlation coefficient of 0.94, indicating that the synchronous instability of the main structure of the aggregates in the interval was the common driving point of the release of multiple pollutants. On this basis, the safety disturbance control interval for the actual elution operation was set as , and was taken as the main reference point for dynamic regulation. In the A lake dredging elution operation, the disturbance system was deployed in conjunction with the magnetic adsorption particles for synchronous capture and control of heavy metals, the test area was 500 m2, the disturbance period was 48 hours continuously, and through the tracking record of the online monitoring system, it was found that the pollutant release curve had no sudden jump trend in the disturbance operation, the daily average release of TP was controlled at 1.2±0.15 mg / L·min, the fluctuation amplitude of COD was less than ±0.3 mg / L·min, the concentration of heavy metals was always lower than the limit value of the national surface water class III standard, and the pollutant release was always in the response stable interval predicted by the model.

[0058] This embodiment carried out a complete disturbance-response-feedback closed loop test in the southeast sedimentation area of A lake. The average thickness of the sediment in this area was 58 cm, the pollution aggregate enrichment area was concentrated in the upper 25 cm layer, the aggregate was mainly organic-mineral composite structure, the particle size range was 30-100 μm, and contained high concentrations of total phosphorus (TP: 2.3-2.6 mg / g), ammonia nitrogen (NH4+-N: 1.5-1.8 mg / g), chemical oxygen demand (COD: 15.0-19.5 mg / g) and heavy metals , , , etc. It was preliminarily identified that the content of extracellular polymeric substance in the aggregate structure of this area was rich, the shear resistance was medium-low, and the structure disintegration had obvious shear sensitivity. In the early stage of the disturbance test, the disturbance shear rate was set in the range of to carry out pre-test by segmentation, the unit time release rate of pollutants was collected, and the change rate of the disturbance input at each moment was measured, so as to construct the disturbance influence function for fitting calculation, and the non-public disturbance-response function proposed by the application was used:

[0059]

[0060] In the actual data into the process, the parameters are selected as follows: disturbance sensitivity coefficient Set to 0.06-0.10 (according to the rate of agglomerate disintegration), release reaction adjustment coefficient Set to 1.2-1.5 (affect the pulling range of shear term on Ψ), 0.6-1.0 (the influence degree of release reaction term), pollutant release inhibition decay coefficient Take 0.12-0.18 (reflect the delay response characteristics of the system to pollution release), structure disturbance period parameter Set to 1.8-2.2 (reflect the structure non-stable period characteristics of agglomerate in disintegration process), disturbance intensity The test range is , the time period Set to the disturbance start to 60 minutes continuous operation window.

[0061] After the above data is substituted into the model, the nonlinear integral curve of is obtained, wherein in the range of , The curve slope is the slowest and the amplitude is stable, and it enters the platform interval of the function, which represents that the disturbance intensity in this range can cause controllable disintegration of agglomerate structure and stable growth of pollution release rate without mutation. The monitoring system shows that the TP release rate is stably controlled at 0.85-1.03 mg / L·min, The control is 0.67-0.72 mg / L·min, the COD fluctuation is less than ±0.4 mg / L·min, and the heavy metal release concentration does not exceed the limit value of "Surface Water Environmental Quality Standard" (GB3838-2002) III.

[0062] On the contrary, when the disturbance intensity is increased to , The value rises rapidly and is accompanied by high-frequency fluctuations, corresponding to the peak value of TP release in the monitoring results rising to 1.9 mg / L·min, and the COD instantaneously increasing to 7.2 mg / L·min, indicating that the disturbance has exceeded the system safety threshold and the pollution release is out of control. In the elution process, the system takes the stable interval of as the disturbance control basis, locks the nonlinear threshold interval to , and sets the stable value interval of 0.38-0.52 as the trigger judgment standard. The disturbance equipment operating parameters are adjusted in real time by the self-adaptive PID adjustment algorithm to adjust the disturbance frequency and shear impeller angular velocity, so as to maintain the disturbance intensity in the platform interval.

[0063] In actual operation, online monitoring showed that the TP release rate increased by more than 0.3 mg / L·min within a certain period of time, and the system automatically detected this. The value is approaching the upper threshold ( The perturbation shear rate was then changed from Reduced to The system was paused for 3 minutes before resuming operation, effectively avoiding the risk of sudden pollutant release. In the engineering test area (treatment area 720 m²) operating continuously for 72 hours, the overall disturbance system response was adjusted a total of 46 times, maintaining high stability in pollutant release. The peak TP concentration in the water was controlled below 2.7 mg / L, and the release process never exceeded the threshold range set by the model. This experiment fully demonstrates that utilizing the dynamic response function of disturbance shear rate and pollutant release rate is effective. It is possible to construct a well-defined and calculable perturbation plateau region by introducing an adjustment coefficient. The formation of a mathematical characterization of structural disintegration and release behavior, and the realization of real-time closed-loop control of disturbance input and release output during actual elution process, is an important technological advancement that breaks through the traditional experience-based judgment of disturbances and moves towards intelligent feedback of dynamic parameters. It is particularly suitable for lake and river sediment remediation projects with complex pollution types, strong hydrodynamic fluctuations, and high structural heterogeneity, and has extremely high engineering replication value and water environment governance safety assurance efficiency.

[0064] Example 3:

[0065] Combined with appendix Figure 6 As shown, this embodiment continues the engineering test in the sedimentary area on the south bank of Lake A. This area is the secondary treatment section after the previous disturbance and elution test. After controlled disturbance and disintegration, the sediment aggregates have released a large amount of pollutants, mainly including total phosphorus (TP) concentration of approximately 2.8 mg / L and ammonia nitrogen (…). The concentration of pollutants was approximately 1.9 mg / L, and the COD reached 16.5 mg / L. Furthermore, due to the dense distribution of aggregates in some areas, the release was delayed, and pollutants may still slowly rise after the disturbance ends, posing a risk of secondary pollution. Therefore, after the disturbance stops, a secondary buffer layer at the water-sludge interface is constructed to inhibit the upward diffusion of pollutants and stabilize the release flux.

[0066] First, 5 minutes before the disturbance equipment stops operating, gradually reduce the shear frequency from the original setting. Down to , and the fluid recirculation pump speed was reduced simultaneously, so that the overlying water velocity decreased slowly from 0.18 m / s to 0.03 m / s, and remained static for more than 30 minutes, forming a stable hydrodynamic mitigation zone. At this stage, the particulate pollutants in the water body began to settle naturally. Laser particle size analysis showed that the settling rate of pollutant particles with a particle size of 15-45 μm was 0.6-1.1 mm / min, and it was expected that the transfer process from the water body to the interface would be completed within 2 hours. Subsequently, iron-modified porous biochar particles and chitosan-based cationic gel particles were uniformly added to the water-mud interface in the test area, with dosages of 2.5 kg / m² and 1.2 kg / m², respectively, which were responsible for the adsorption and complexation of phosphorus and heavy metals, respectively. Monitoring showed that the total phosphorus in the raw water decreased from 2.8 mg / L to 1.1 mg / L within 90 minutes, the concentration decreased from 0.036 mg / L to 0.011 mg / L, and the pollutants were effectively fixed on the surface of the particles after release, entering the retention period.

[0067] To further stabilize the resuspension potential of pollutants on the surface of the sediment, the microenvironment of the water body was adjusted after the adsorption material was added. The pH at the interface was adjusted from the initial 8.1 to 7.4 using an acid-base buffer solution to reduce the resolubilization rate of phosphorus, a microelectric field of 0.3 V potential difference was applied to enhance the ion exchange capacity of the interface to solidify , and dilute iron oxireductant was injected to increase the ORP value from +180 mV to +280 mV, forming a micro-oxygen state to promote the stabilization of the oxidized form of heavy metals. After the above control operations were completed, the concentration of pollutants within 5 cm of the interface was monitored over time, and the results showed that the pollutants were basically stable within 2-4 cm of the upper surface of the sediment within 12 hours, and the proportion of particulate-bound phosphorus and heavy metals increased by more than 60%, forming a secondary buffer layer with adsorption + stabilization + slow release functions, with a sedimentation structure thickness of about 3.2 cm, and a retention time that can be stably maintained for more than 72 hours without obvious floating trend. To evaluate the stability of the project, under the conditions of simulated rainfall and slight disturbance (flow rate increased to 0.08 m / s) for the next 5 days, the TP concentration in the interface buffer layer was always less than 1.4 mg / L, and the COD did not fluctuate dramatically, the average release flux was controlled at 0.18 mg / m²·h, and no resolubilization peak of heavy metals was observed, indicating that the structure has excellent dynamic slow release and anti-disturbance ability.

[0068] This example carried out a test in the slow-flow area near the shore in the middle of Lake A. After the previous disturbance and elution operation, there was a tendency for partial pollutant slow release rebound in this area, with TP increasing from 1.4 mg / L to 1.9 mg / L within 48 hours after the disturbance ended, The concentration is maintained at 2.1-2.3 mg / L, and the ORP value of the overlying water of the sediment is continuously below +150 mV, indicating that part of the pollutants released is not effectively deposited and there is an interface migration risk. Therefore, according to the method described in the present application, an interface pollution control intervention measure is set, first, three typical guided sedimentation materials are selected for performance comparison pre-test, including (1) modified bentonite (surface negative charge capacity ≥ 90 mmol / kg); (2) iron modified corn straw biochar (specific surface area 850 m² / g); (3) powdered zeolite and calcium carbonate composite particles (diameter 0.3-0.6 mm). The comparison results show that the modified biochar has the strongest adsorption capacity for TP and COD, and the modified bentonite has obvious effect on heavy metal charge capture, and the final combined formulation is a mixture of biochar and bentonite composite particles at a ratio of 3:1, and the dosage density is set to 3.5 kg / m².

[0069] The uniform dosage starts at 3 hours after the end of elution, the material is settled in 3 hours and covers the upper 0-3 cm area of the water-mud interface, the particle size distribution is good, and no secondary floating occurs, then the microenvironment regulation of the interface layer starts, the pH is stably controlled at 7.2-7.4 by slow-release acid-base regulator to avoid acidic dissolution or basic desorption causing phosphorus re-release, then slow-release oxidizing agent (composite peroxide capsule, release period > 96 hours) is added to adjust the interface ORP to +280-+310 mV to control the heavy metals to be deposited in oxidized state, and finally the directed proliferation type microbial regulator (strengthened nitrosation bacteria and phosphorus solubilizing bacteria at a ratio of 1:3) is introduced to promote the synchronous transformation of nitrogen and phosphorus.

[0070] The monitoring data show that within 24 hours after the addition of the settling material, the TP concentration decreases from 1.9 mg / L to 1.2 mg / L, and within 72 hours, it further decreases to 0.88 mg / L, and the COD decreases from the initial 7.4 mg / L to 5.1 mg / L, from 0.027 mg / L to 0.011 mg / L, and remains within 1.5 mg / L without rapid rebound, and the interface ORP fluctuation amplitude is controlled within ±15 mV, indicating that the microenvironment regulation is stable and reliable. On the 5th day, a shallow disturbance test (artificial disturbance flow 0.08 m / s, lasting 30 minutes) is carried out, the interface particle structure is not damaged, the pollutant concentration is slightly disturbed and increased, but does not break through the original platform value, the TP fluctuation is only 0.18 mg / L, and the COD increases by 0.5 mg / L and then quickly falls, indicating that the interface buffer layer constructed by the combination of "charge adsorption + specific surface adsorption + oxidation stabilization + microbial regulation" has high anti-disturbance ability and pollutant stable control ability.

[0071] Further calculation of adsorption capacity and deposition retention rate, the unit adsorption capacity of the composite particles for TP is 42.3 mg / g, and for COD is 59.7 mg / g, the heavy metals and The concentrations were 0.56 mg / g and 0.38 mg / g, respectively; the sediment retention rate reached over 89% within 7 days, significantly higher than the single-material addition group (67–72%). These results demonstrate that the material addition scheme employed in this invention, characterized by charge adsorption capacity and high specific surface area, can induce pollutant aggregation, sedimentation, and fixation at the water-mud interface. Simultaneously, through a three-dimensional synergistic regulation mechanism of pH, redox potential, and microbial structure, it efficiently deposits released pollutants into the shallow surface layer of the sediment, constructing a stable sedimentary structure and significantly reducing the risk of secondary migration of disturbed released pollutants.

[0072] After completing the routine shear elution test (the disturbance intensity was set at...), this area... (The system operated continuously for 6 hours, treating an area of ​​1000 m²). Although the aggregate structure had been effectively disintegrated and the pollutant release process was in a plateau phase, online monitoring showed that in the first 6 hours after the disturbance stopped, the total phosphorus concentration dropped from 1.8 mg / L to 1.2 mg / L and then rebounded, rising to 1.5 mg / L within 72 hours. Ammonia nitrogen remained between 2.0 and 2.2 mg / L for 48 hours, indicating a risk of "partial pollutant incomplete settling + re-migration of released pollutants." Especially under the conditions of decreased water temperature and weakened convection at night, the pollutant concentration in the bottom water increased significantly. Therefore, the continuous secondary buffer layer construction process proposed in this invention was immediately initiated.

[0073] The first step of the process is dynamic monitoring of flow velocity during the disturbance reduction period. When the flow velocity drops below 0.05 m / s and remains stable for more than 30 minutes, the disturbance is considered to have ended. The second step is to quickly start the interface adsorption layer construction program by uniformly adding porous particulate material (particle size 0.2–0.6 mm, specific surface area 890 m² / g, dosage 3.2 kg / m²) composed of modified zeolite, biochar particles, and clay minerals to the water-sludge interface of the treatment area. During the addition process, a multi-point settling and distribution device is used to ensure uniform distribution and prevent flocculation. The third step is to start the slow-release control module by simultaneously adding slow-release pH adjusting particles (composite phosphate derivative, release cycle 72 h) and a low dose of oxidative stabilizer (stabilizing type) to the buffer layer. The complex (release period 96h) was used to control the interface pH at 7.3–7.6 and maintain ORP in the range of +260–+300mV. The fourth step involved deploying a shallow-layer monitoring probe array to monitor total phosphorus, ammonia nitrogen, COD, and other pollutants in the 0–5cm layer. Dynamic tracking of indicators showed that within 24 hours of buffer layer construction, total phosphorus in the water decreased to 0.85 mg / L, and stabilized at 0.72 mg / L after 48 hours. Ammonia nitrogen decreased from the original 2.1 mg / L to 1.6 mg / L, and heavy metals... The concentration of TP decreased from 0.024 mg / L to 0.010 mg / L, and the pollutant retention rate of the superficial layer of the sediment was significantly improved. The average TP concentration in the 0-3 cm layer detected by solid-liquid separation was 1.9 mg / g, indicating that the released pollutants were effectively captured again.

[0074] To verify the anti-interference ability, artificial disturbance test was started on the 5th day, simulating natural wind and seepage disturbance (flow rate increased to 0.1 m / s, disturbance time 30 minutes), after the test, the water body TP only increased from 0.72 mg / L to 0.88 mg / L, and fell after 30 minutes, indicating that the interface structure stability and buffering capacity are good, and it has the ability to inhibit pollution after disturbance. During the whole test process, the construction of the buffer layer lasted only 2 hours from the closing of the disturbance equipment to the completion of the feeding, realizing seamless connection with the elution process, and there was no pollution window period. Finally, based on the evaluation model of disturbance shear strength , pollutant release rate , residual sediment load , the buffer capture efficiency :

[0075]

[0076] Among them represents the total residual pollutant load in the overlying water body after disturbance, is the average pollutant concentration in the water body after the formation of the buffer layer, is the water volume of the disturbance control area. Substituting the data ( , , ), the calculation can be obtained , indicating that the buffer layer has strong and stable re-capturing ability for residual pollutants after disturbance, effectively bridging the system transition problem between disturbance-release-sedimentation-re-solidification. In summary, the secondary buffer layer constructed in the application not only can capture the pollutants that have not been fully settled in the post-disturbance stage, but also can form reverse migration inhibition for the pollutants that have floated, its construction process and elution operation process are dynamically continuous and automatically connected, effectively supporting the closed loop process design of sediment disturbance treatment, and is suitable for the safe regulation and control scene in the in-situ remediation engineering of medium and large lake eutrophic sediment, which is a key technical supplement for the pollution re-control ability that traditional elution technology cannot achieve.

Claims

1. A method for eluviation of river and lake sediments with controllable release of aggregate pollutants, characterized in that The method comprises the following steps: The sensitivity of the bottom mud to disturbance is determined by measuring the micro-agglomerate binding energy including electrostatic force and organic cementation strength in the bottom mud; a stress response relationship of the agglomerate is established to predict the structural disintegration behavior under the disturbance shear rate; the agglomerate is divided into an easy-to-break type, a controllable breaking type and a stable type; The disturbance parameters of the shear rate and fluid kinetic energy are fitted with the release rate of the pollutants to determine a non-linear threshold interval; A disturbance threshold window is set to make the disturbance energy between the decomposition starting point of the agglomerate and the overflow point of the pollutants; the disturbance rhythm is controlled to guide the orderly disintegration of the agglomerate; The interface conditions of pH and potential difference are used to adjust the diffusion of the pollutants in the interface layer; the released pollutants are guided to form charge exchange and complex reactions with the natural clay layer and the charge-adjusting particles of the in-situ control agent; the release path of the pollutants, the interface and the water body is controlled to make the pollutants form a retention layer in the interface; the steady-state relationship between the disturbance input and the pollution release output is dynamically coordinated, the residual pollutants after release are settled to the surface layer of the bottom mud through the interface retention layer, and a secondary buffer layer is constructed.

2. The method for eluting river and lake sediments with controlled release of aggregated pollutants according to claim 1, characterized in that... The method for predicting the structural disintegration behavior under the disturbance shear rate comprises: The structural characteristics of the pollution agglomerate in the bottom mud are analyzed in-situ to obtain the particle size distribution, component composition, bonding type and cementation strength information of the agglomerate; a mapping relationship between the disturbance shear rate and the structural response of the agglomerate is established to predict the structural integrity change trend of the pollution agglomerate under a given disturbance shear rate, and a key structural breaking point is identified.

3. The method of claim 2, wherein the controllable release of aggregate pollutants from the lake sediment is controlled by the amount of the at least one of the one or more biodegradable polymers and the one or more biodegradable copolymers. The structural characteristics of the agglomerate include the physical combination and chemical bonding state among inorganic particles, organic matter and microbial extracellular polymers; the mapping relationship between the disturbance shear rate and the structural response of the agglomerate is established based on the gradual change process of the structural deformation, micro-crack formation and cementation failure of the agglomerate under disturbance; the key structural breaking point refers to the critical disturbance shear rate at which the main combination structure in the agglomerate reaches the failure state.

4. The method of claim 1, wherein the method is a method of controllably eluting aggregate-bound contaminants from a lake or river sediment. The method for determining the non-linear threshold interval comprises: The pollution release rate data of the pollution agglomerate under different disturbance shear rates or fluid kinetic energy conditions are obtained, and a continuity curve between the disturbance shear parameters and the pollution release response is established; A release acceleration change inflection point in the response curve is identified as the critical strength of the rapid release of the pollutants; The release stable interval and the disturbance range before the release mutation are jointly defined as the non-linear threshold interval of the disturbance control; the threshold interval is used to adjust the disturbance intensity of the bottom mud elution operation.

5. The method of claim 4, wherein the controllable release of aggregate pollutants from the lake sediment is controlled by the addition of a chemical agent to the lake sediment. 5 The pollutants include one or more of total phosphorus, ammonia nitrogen, chemical oxygen demand (COD) and heavy metal ions; the continuity response curve is a non-linear relationship curve between the disturbance shear rate and the pollution release amount per unit time, which is used to identify the mutation critical point of the pollution release in the disturbance process.

6. The method of claim 5, wherein the controllable release of aggregate pollutants from the lake sediment is controlled by the amount of the at least one of the one or more biodegradable polymers and the one or more biodegradable copolymers. The non-linear threshold interval is established by collecting multiple sets of pollution release data under different disturbance intensities and dynamically corrected according to the real-time data in the actual elution process; the non-linear threshold interval is used to control the operating parameters of the disturbance equipment, so that the disturbance intensity is within the stable release range of the pollutants.

7. The method of claim 1, wherein the method is a method of controllably eluting aggregate-bound contaminants from a lake or river sediment. The method for constructing the secondary buffer layer comprises: forming a flow velocity reduction zone at the water-sediment interface to promote the settlement of pollutants by regulating the hydrodynamic conditions of the disturbance stop phase; and releasing a guided settlement material at the water-sediment interface region for adsorbing or complexing the released pollutants; and making the settled pollutants form a retention deposition structure on the surface layer of the sediment by adjusting the microenvironment parameters of the interface layer, including pH, potential or redox conditions.

8. The method of claim 7, wherein the controllable release of aggregate pollutants from the lake sediment is controlled by the amount of the at least one of the one or more biodegradable polymers and the one or more biodegradable copolymers. The guided settlement material is a material with charge adsorption capacity or high specific surface area, selected from modified clay, biochar, zeolite or composite particle materials thereof; and the microenvironment parameters of the interface layer are controlled by adding acid-base regulators, slow-release oxidizing agents or microbial regulators to stabilize the deposition state of the pollutants in the surface sediment.

9. The method of claim 7, wherein the method further comprises The secondary buffer is used for capturing residual pollutants that have not completely settled or have entered the water body after disturbance; and the construction process of the secondary buffer layer is continuously connected with the disturbance elution process, forming a closed-loop pollution control process of disturbance control, pollution release, re-settlement and interface stabilization.

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